Rotary hook mechanism for sewing machines



April 11, 1944.

'w. MYERS ROTARY HOOK MECHANISMS FOR, SEWING MACHINES Filed Aug. 15', 1942 2 Sheets-Sheet 1 w. MYE S ROTARY HOOK MECHANISMS FOR SEWING MACHINES April 11, 1944.

Filed Aug. 13, '1942 v 2 Sheets- Shee1i2 Myers Patented Apr. 11, 1944 nane:

ROTARY HOOK MECHANISM FOR SEWING MACHINES Walter Myers, Bridgeport, Conn, assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application August 13, 1942; Serial-No; 454,655

10 tClaims.

This invention relates to lubricating devices for the thread-carrier raceways of rotary loop-takers for sewing machines and, more particularly, for the thread-carrier raceways of vertical-axis looptakers of the rotary hook type.

The present invention aims to provide simple and efiicient means for delivering lubricant to the raceway of a rotary loop-taker. A more specific object of the invention is to provide looptaker raceway lubricating means functioning to minimize overheating of the loop-taker and of the journaling means in the vicinity of the looptaker, thereby to increase the life of the looptaker. Other objects of the invention will be apparent from the following description and claims.

The invention consists in the lubricant collecting and delivering means hereinafter describedin connection with the accompanying drawings, which illustrate two forms of the improvement and in which:

Fig. 1 represents an enlargedivertical section, partly in front elevation, of a portion of a sewing machine containing the improved loop-taker mechanism. Fig. 2 represents a horizontal section of the loop-taker hub shown in Fig. 1, the section being taken substantially on the line 2-2 of Fig. 1. Fig. 3 represents an enlarged fragmental view, similar to Fig, 1 and. showing a modified form of lubricant. collecting and distributing means. Fig. 4 represents a horizontal section of 'the hub of the looptaker illustrated in Fig- 3; the. section being taken substantially on the. line 4- 5 of Fig. 3..

The sewing machine which isin part illustrated in the drawings has the usualbed l. provided with the work-supporting slide-plates 2 and 3, and with a throatrplate .4 disposedbetween said slideplates.

Depending from the bed I is a. lug 5 provided with a horizontally apertured bearingebushing- 5. A loop-taker and feed-actuating shaft 1' is 110-- tatably journaled in the bearing-bushing t to extend horizontally lengthwise of they bed I. Carried by the-rotary shaft 1 is agreed-lift eccentric 8- engaged by a feed-bar Sprovided with a Work-advancing feed-dog It. The'feed-dog I0 operates through feed-slots H provided in the throat-plate 4i and-is actuated to cooperate, ina conventional mannenwith one or'more endwise reciprocatory and laterally vibratory threadcarrying needles I 2 in advancing" the work; The. feed-dog It) is opposed by the, usual spring,-. depressed presser-foot l3.

Complemental to the right hand needle l2, inthe formation of lock-stitchesisa rotary looptaker M of the vertical-axis rotary hook type, i. e., of the type in which-the hook rotates about an axis substantially normal to the work-support. The rotary hook 14 has a cup-shaped body including a bottom'wall l5 and a generally cylindrical side wall [6.

Journaled in a raceway it" provided in the side wall It of therotary hook body is a threadcarrier l1 restrained against rotation with the rotary hook. The bottom wall 15 of the rotary hook is externally provided with a depending annular flange I8. concentric with a vertically disposed rotary hook shaft l9 of which the upper end is preferably integral with the hook. The radiusof the hub-flange l8is preferably substantially shorter'than that of the side wall iii of the rotary hook. The hook-shaft I9 has a longitudinal bore which extends through the bottom wall l5 and its flange l8 of the hook-body, and the-upper end of said bore terminates in a countersink 2| in the inner face of the hook bottom wall iii. The hook-shaft bore 20 opens into an enlarged counterbore 22 formed i the lower portion of the hook-shaft I9. Disposed in said counter-bore 22 is the reduced stem 23 of an eccentric 24 held in engagement with the lower end of the shaft l9 by a screw 25; To this end, the screw 25 is passed downwardly through the bore 20 of the hook-shaft and is threaded into the stem 23 of the eccentric 24; the head 25 of said screw being disposed in the countersink 2| of the hook-body. The eccentric 24 is locked to the hook-shaft 19 for rotation in timed relation therewith by means of. a pin 26 extending transversely through the stem 23 of the eccentric and entering suitable notches, as 21, in the lower end of the hook-shaft.

The hook-shaft I8 is rotatably supported by a bracket or hook-saddle 28 whichis disposed below the work-support of. the machine and, as usual, is in part supportedby a reduced portion 6. of thebearing-bushing 6. The bracket 28 is cutaway to provide a gear-clearance cavity 29 between vertically spaced walls 36, and 3i. The upper wall 30 of thebracket has a vertical shaftclearance opening 32; said wall 38 being provided in its upper face with an annular cavity 33; said cavity forming an oil-cup into which. the hub-flange E3 of the rotary'hook. depends. The wall 30 is provided inits lower facewith a ballbearing cavity 34. Thehook-shaft I9 is slightly 3 enlarged, adjacent. the-bottomwall [5 of the hook to form a, shoulder I9 resting upon the bottom wall of the cavity 33. The lower wall 3| of the bracket 28 is likewise provided with an annular opening 35 which is coaxial with and is, in the present case, diametrically of substantially the same size as the lower cavity 34 of the upper wall. The lower portion of the opening 35 of the lower wall 3| is enlarged to provide a threaded counterbore 36.

Detachably secured by a screw 31 upon the hook-shaft l3, intermediate the ends thereof, is the hub 38 of a spiral pinion-gear 39. The hub 38 of the pinion-gear comprises, in effect, a tubular sleeve having the pinion-gear teeth disposed medianly between the opposite ends of the sleeve. I

The hub-sleeve 38 has diametrically reduced endextensions 33 and 3 I, upon each of which is forcefitted the inner race-ring of a ball-bearing 42. The outer race-ring of the upper ball-bearing 42 is slip fitted into the ball-bearing cavity 34 in the upper bracket-wall 33, and the outer racering of the lower ball-bearing 42 is similarly fitted into the opening 35 of the lower bracket wall 3!. The outer race-ring of the lower ballbearing 52 is circumferentially grooved to receive a conventional split abutment-ring 43 adapted to engage the bracket-shoulder formed by counterboring the lower bracket-wall opening 35. The assembly unit, comprising the pinion-sleeve 33 and the ball-bearings carried thereby, is vertically positioned in the bracket 28 by a screwplug 45 threaded into the counterbore 33 of the bracket-wall 3! to hold the abutment-ring 43 in engagement with the bracket-shoulder 44.

The pinion-gear 39 is engaged, in the usual manner, by a spiral-gear having its hub 46 suitably secured upon the shaft 1, the ratio of said gears being such that the hook-shaft l9 rotates twice for eachrotation of itsdriving shaft 1. The bracket-cavity 29, in which the hook-shaft driving gears are disposed, isclosed by a detachable end-closure plate 4'! disposed adjacent the feed-bar 9.

As more fully described in my prior Patent No. 2,236,830, April 1, 1941, the eccentric 24 engages the fork of a crank-arm 48 carried by the lower end of a vertically disposed rock-shaft 49. The rock-shaft 39 is journaled eccentrically in a bushing 53 secured for turning adjustment in the bracket 28 by a screw At its upper end, the rock-shaft 39 carries .escapement-flngers, as 52, adapted. to enter apertures, as 53, provided in the thread-carrier i1, thereby to restrain the thread-carrier against rotation with the rotary hook. Detachably secured upon the bottom wall of the supporting bracket 28 is a dished closureplate 54 which houses the hook-shaft eccentric 24 and the crank-arm 48 actuated thereby, said closure-plate also functioning as an oil-holding reservoir.

The present invention resides more particularly in supplying lubricant to the thread-carrier raceway of the rotary hook. In the form of the improvement illustrated in Figs. 1 and 2 of the drawings, the upper wall 3!] of the bracket 28 is provided with a horizontal inlet-aperture 55 connected, in any suitable or preferred manner, to a lubricant supply reservoir (not shown) which is disposed above the level of the hook and is manually regulatable to control the quantity of lubricant gravitationally delivered to the aperture 55. However, any other suitable lubricant supplying means may be employed. The aperture 55 of the wall 33 is connected by a short duct 56 with the upper face of thebottom wall of the oil-cup cavity 33, at a point in said face within the area circumscribed by the hub-flange 18 of the rotary hook.

The hub-flange it depends into close proximity to the bottom wall of the oil-cup cavity 33 and is encircled by the side Wall of said cavity; said side wall of the cavity being disposed in close proximity to the flange IS. The circumferentially inner face 5'! of the flange I8 is preferably undercut and is therefore outwardly inclined upwardly. Disposed within the flange l8, for rotation with the hook, is a lubricant-absorbent substance as, for example, a felt-ring 53 which is preferably in wiping contact with the bottom wall of the cavity 33. Leading from the upper edge of the inclined flange-face 51 is an outwardly and upwardly inclined duct 69 connected to another duct 5! terminating in the thread-can rier raceway E6 of the rotary hook; said ducts 6!], 6| being provided in the bottom and side walls of the hook.

In the operation of the machine, the lubricant supplied to the oil-cup cavity 33, through the bracket-wall ducts and 56, is picked up by the lubricant-absorbent material 59 which rotates with the rotary hook. The picked-up lubricant is thrown centrifugally outwardly and is caught by the undercut flange-face 51; said face directing the lubricant upwardly toward the upper edge thereof, Lubricant is thereby delivered to the rotary hook duct 60, through which duct the lubricant passes centrifugally to the duct 3! and thence to the rotary hook raceway. Should excess lubricant be inadvertently delivered through the ducts 55, 58 when the machine is idle, the lubricant is free to drain downwardly through the shaft-clearance opening 3?. and into the gear-cavity of the bracket 28.

It will be noted from Fig. 1 of the drawings that the bottom wall l5 of the hook is in close proximity to but is spaced slightly'from the upper face of the bracket-wall 30 outwardly of the hub-flange I8. It will be further noted that the hub-flange l8 has a conical outer face, whereby the inner and outer faces of the flange are upwardly convergent and said flange functions as an oil-sling. As the lubricant is supplied through the duct 53 to the oil-cup cavity 33 at a point within the hub-flange l8 of the rotary hook, the

oil-sling action of the outer face of said flange iii in no wa interferes with the delivery of lubricant to the inner face 5'! of the hub-flange In the modification illustrated in Figs. 3 and 4 of the drawings, the upper wall 30 of the bracket 28 is provided with a ball-bearing opening 62 which is counterbored from the upper face of said wall 30 to form a clearance-opening 63 which is diametrically very slightly larger than the rotary hook hub-flange l8 embraced by the wall Of said opening 63. Seated in the opening 63, in vertically spaced relation to the ball-bearing 42 and so as to be restrained against rotation with the rotary hook i4, is a hardened insert 64 having a central shaft-clearance opening 65; said insert 64 having a centralflange 66 extending upwardly into close proximity to the bottom wall I5 of the rotary hook. Th thickness of the insert 64 is substantially less than the depth of the counterbore-opening 63, whereby the wall of said opening 63 and the flanged insert 64 together form a lubricant-collection cavity. The insert 64 has a horizontal duct 61 alined with the bracket inlet-aperture 55 described in connection with Fig. 1; said duct til-being connected-by a vertical aperture 38- with the upper face of the insert 64, at a point in said face within the area circllgmscribed by the hub-flange lb of theerotary hoo The lower face of the bottom wall lb of the rotary hook-and the upper face of the inserttd are-held spaced from each other by a plurality of thrust-bearing and lubricant-distributingballs 69. The balls 69 are heldseparated'from each other by a cage-disk Ill-provided with a plurality of peripheral ball-receiving notches H which permit radial movement of the balls 66, under centrifugal force, into engagement with the -hubflange l8'ofthe rotar hook. The cage-disk iii has a central aperture to'embrace the insertflange 66 and to provide for turning movement of said disk about said flange 6-6.

Lubricantsupplied through the wall-duct EE- and' the insert-ducts 61 and 68' to the upper face of the insert is picked up by the ballstfi; in theoperation of the machine, and is'deliveredf by the rotating balls Gttotheinner face El ot the hub-flange I8, from which the lubricant is supplied to the hook racewayin the same manner as before described.

The balls 69 also function as an anti-iriction support for therotary hook Win aform of con' struction providing for convenient replacement of the rotary hook.

Havingthus set forth the nature of the-invention, what I claim herein is: 1

1. In a sewing machine, in combination, a ro- Cir tary hook-having a body providing a bottom wall anda cylindricalside wall; said sidewall being provided with a thread-carrier raceway, and said bottom wall being externally provided with an annular flange'having an undercut inner side face, a thread-carrier journaled in said raceway and restrained against rotation with said hook; a lubricant-collecting cup having a side wall encircling said flange in close proximity thereto; a lubricant-supply conduit opening into said cup at a point within an area circumscribed by said flange; and lubricant conducting connections between said undercut face of the flange and said raceway.

2. In a sewing machine, in combination, a rotary hook having a body providing a bottom wall and a cylindrical side wall; said side wall being provided with a thread-carrier raceway, and said bottom wall being externally provided with a depending annular flange having an inner side face inclined outwardly in an upward direction; means for rotating said hook about a vertical axis; a thread-carrier journaled in said raceway and restrained against rotation with said hook; a lubricant-collecting cup having a bottom wall disposed in close proximity to and havin a side wall encircling said flange; lubricant-conducting connections with the upper face of the bottom wall of said cup at a point within an area of said face circumscribed by said flange; and lubricant-conducting connections between said inner face of the hook-flange and said raceway.

3. In a sewing machine, in combination, a. 1'0- tary hook disposed for rotation about a vertical axis and having a body providing a bottom wall and a cylindrical side wall; said side wall being provided with a thread-carrier raceway, and said bottom wail having a depending circular flange formed with upwardl convergent opposed side faces; means for rotating said hook; a thread carrier journaled in said raceway and restrained against rotation with said hook; a rotary hook supporting bracket provided with an upwardly open lubricant-collection cavity; said cavity hav ing a bottom wall disposed in close proximity to said flange, and said cavity having aside wall encircling said flange and underlying said bottom. Wall of the rotary'hook in close proximity thereto; a lubricant-inlet conduit connected with said cavity in an area circumscribed by said flange; and a lubricant-conduit connecting the inner face;& of said flange and said raceway of the rotary hoo 4. In a sewing machine, a supporting bracket provided in its upper face witha lubricant-collecting cavity having a cylindrical side wall and a substantially flat bottom wall formed centrally thereof with a clearance opening; a shaft journaled in sa-idbracket for rotation about a vertical axis and extendin through said clearance opening; a rotary hook carried by-the upper endcf said shaft andhaving a cylindrical side wall provided with-a thread-carrier raceway; said rotary hook having a bottom wall provided with a circular flange spaced from saidshaft and depending into said cavity; a thread-carrier journaled in said hook and restrained against rotation therewith; a lubricant-inlet conduit connected with said cavity; a ring of lubricant-conducting material embracing said shaft within said flange, said ring being disposed in contact with the inner face of said flange; and a lubricant-conduit connecting the inner face of said flange with said raceway of the rotary book.

5. In a sewing machine, in-combination, a rctary hook having a-b'od providin a bottom wall and a cylindrical side wall; said side wall being provided with a thread-carrier raceway, and said bottom'wall being externally provided with a depending annular flange; means for rotating said hook about a vertical axis; a thread-carrier journalecl in said raceway and restrained against rotation with said hook; a lubricant-cup having a bottom wall disposed in close proximity to and having a side wall encircling said flange; a lubricant-supply conduit extending through the bot tom wall of said cup and terminating in the upper face of said bottom wall at a point within an area circumscribed b said flange; lubricantconducting means disposed within said flange for delivering lubricant from said cup to the inner side face of said flange; and lubricant-conducting connections between said inner side face of the hook-flange and said raceway.

6. In a sewing machine, in combination, a rotary hook having a bod providing a bottom wall and a cylindrical side wall; said side wall being provided with a thread-carrier raceway; and said bottom wall being externally provided with a depending annular flange; means for rotating said hook about a vertical axis; a thread-carrier journaled in said raceway and restrained against rotation with said hook; a lubricant-cup having a bottom wall disposed in close proximity to and havinga side Wall encircling said flange; lubricant-conducting connections with said cup; lubricant conducting means disposed within said flange and rendered effective upon rotation of said hook for delivering lubricant from said cup to the inner side face of said flange; and lubricant-conducting connections between said inner side face of the hook-flange and said raceway.

7. In a sewing machine, in combination, a rotary hook having a body providing a bottom wall and a cylindrical side wall; said side wall being provided with a thread-carrier raceway, and said bottom wall being externally provided with a depending annular flange; means for rotating said hook about a vertical axis; a thread-carrier journaled in said raceway and restrained against rotation with said hook; at lubricant-cup having a bottom wall disposed in close proximity to and having a side wall encircling said flange; lubricant-conducting connections with said cup; a lubricant-absorbent material disposed within said flange in wiping contact with the bottom wall of said lubricant-cup; and lubricant-conducting connections between the inner side face of the hook-flange and said raceway.

8. In a sewing machine, in combination, a rotary hook having a bod providing a bottom wall and a cylindrical side wall; said side wall being provided with a thread-carrier raceway; and said bottom wall being externally provided With a dependin annular flange; means for rotating said hook about a vertical axis; a thread-carrier journaied in said raceway and restrained against rotation with said hook; a lubricant-cup having a bottom wall disposed in close proximity to and having a side wall encircling said flange; lubricant-conducting connections with said cup; a plurality of balls disposed within said flange, said balls being movable into engagement with the inner side face of the flange and having rolling contact with the bottom wall of said lubricantcup; and lubricant-conducting connections between said inner side face of the hook flange and said raceway.

9. In a sewing machine, in combination, a rtary hook having a body providin a bottom wall and a cylindrical side wall; said side wall being provided with a thread-carrier raceway; and said bottom wall being externally provided with a depending annular flange; means for rotating said hook about a vertical axis; a thread-carrier journaled in said raceway and restrained against rotation with said hook; a lubricant-cup having a bottom wall disposed in close proximity to and having a side wall encirclin said flange; lubricant-conducting connections with said cup; a plurality of balls disposed within said flange, said balls being movable into engagement with the inner side face of the flange and having rolling contact with the bottom wall of said lubricant-cup; a ball-separating cage disposed within said flange; and lubricant-conducting connections between said inner side face of the hookflange and said raceway.

10. In a sewing machine, in combination, a vertical-axis rotary hook having a body providing a substantially horizontal bottom wall and a cylindrical side wall; said side wall having a thread-carrier raceway, and said bottom wall havin a dependin circular flange spaced inwardly from the outer edge of the bottom wall; said flange having an upwardly and outwardly inclined inner face terminatin at its upp r edge in said bottom wall; a thread-carrier journaied in said raceway and restrained against rotation with said hook; a lubricant-collectin cup having a bottom wall disposed in close proximity to the rim of said flange and having a cylindrical side wall embracing said flange; said side wall of said cup being disposed below and extending into close proximity to said bottom wall of the hook externall of said flange; a lubricant-supply duct terminating in the upper face of the bottom wall of said cup at a point within th area circumscribed by said flange; and said body of the hook having an upwardly and outwardlyinclined duct leadin from the inner face of said flange and connected with said raceway.

WALTER MYERS. 

